The package cart-functionality-using-interfaces is designed to implement the cart functionality using Interfaces.

// A Interface named IProduct is defined to contain product following details id: number, name: string, price: number, catogory: string

// A Custom Type having name Cart is defined which contains IProduct array type Cart = { products: IProduct[]; }

// How to use IProduct and Cart // Create a variable of type Cart that can contain IProducts Array let cart1: Cart;

// Now Initialize the Cart variable with products array cart1 = { products: [] };

// Now you can add product in the cart as cart1.products[0] = { id: 10, name: "Pencil", price: 15, catogory: "Stationary" }

cart1.products[1] = { id: 15, name: "Shirt", price: 1500, catogory: "Clothes" }

// A Interface named ICustomer is also defined to store the following information id: number, name: string, email: string

// A custom type is created to sotre a customer and its cart information type Order = { customer: ICustomer, custCart: Cart }

// After that create and Initialize ICustomer variable let cust1: ICustomer = {} as ICustomer;

// Set Value for the Customer cust1.id = 100; cust1.name = 'Asad'; cust1.email = '[email protected]';

// Now create a variable of type Order and initialize it as let ord1: Order = {} as Order; ord1.custCart = cart1; ord1.customer = cust1;

// After that just call the function calcCartAmount(ord1.customer, ord1.custCart);

// It will calcuate and return the amount